Update app.py

app.py

@@ -1,97 +1,88 @@
 import gradio as gr
 import matplotlib.pyplot as plt
 
-def cmda_redevelopment_fsi_calculator(
-    uds, num_owners, old_fsi, new_fsi,
-    guideline_value, market_rate, construction_cost, current_area,
-    builder_share_percent
+def cmda_redevelopment_final_model(
+    uds, num_owners, guideline_value, market_rate, construction_cost
 ):
-    # Step 1: Calculate buildable areas
-    old_area = old_fsi * uds
-    new_area = new_fsi * uds
-    area_gain = new_area - old_area
+    # Step 1: Fixed FSI logic
+    normal_fsi = 2.0
+    premium_fsi = 0.8
+    total_fsi = normal_fsi + premium_fsi
 
-    # Step 2: Premium FSI Charges (only beyond FSI 2.0)
-    premium_fsi_factor = max(0, new_fsi - 2.0)
-    premium_area = premium_fsi_factor * uds
-    premium_fsi_charge = 0.4 * guideline_value * premium_area
+    # Step 2: Area calculations
+    owner_total_area = normal_fsi * uds
+    builder_area = premium_fsi * uds
+    total_built_up_area = total_fsi * uds
 
-    # Step 3: Construction Cost
-    total_construction_cost = new_area * construction_cost
+    # Step 3: Premium FSI Charges
+    premium_fsi_charge = 0.4 * guideline_value * builder_area
 
-    # Step 4: Builder Share
-    builder_share_area = (builder_share_percent / 100) * new_area
-    owner_share_area = new_area - builder_share_area
+    # Step 4: Construction cost for entire built-up area (owner + builder)
+    total_construction_cost = total_built_up_area * construction_cost
 
-    # Resale value based on current market rate
-    resale_value_builder = builder_share_area * market_rate
-    construction_cost_builder = builder_share_area * construction_cost
-    builder_profit = resale_value_builder - construction_cost_builder - premium_fsi_charge
+    # Step 5: Builder Revenue (sale of builder share at market rate)
+    builder_sale_value = builder_area * market_rate
 
-    # Step 5: Owner-wise area (based on UDS)
+    # Step 6: Builder Profit
+    builder_profit = builder_sale_value - total_construction_cost - premium_fsi_charge
+
+    # Step 7: Owner Share Calculations
     uds_per_owner = uds / num_owners
-    new_area_per_owner = owner_share_area / num_owners
-    net_gain_per_owner = new_area_per_owner - uds_per_owner
+    owner_area_per_owner = owner_total_area / num_owners
 
-    # Step 6: Visualization
+    # Step 8: Chart
     fig, ax = plt.subplots(figsize=(6, 4))
-    labels = ['Old FSI Area', 'New FSI Area', 'Premium FSI Area']
-    values = [old_area, new_area, premium_area]
+    labels = ['Owner Area (2.0x UDS)', 'Builder Area (0.8x UDS)', 'Total Area']
+    values = [owner_total_area, builder_area, total_built_up_area]
     ax.bar(labels, values, edgecolor='black')
     ax.set_ylabel("Area (sq.ft)")
-    ax.set_title("FSI Area Comparison")
+    ax.set_title("Redevelopment Share Breakdown")
     plt.tight_layout()
 
-    # Step 7: Output
+    # Step 9: Output
     result = {
-        "Old FSI Buildable Area": f"{old_area:.2f} sq.ft",
-        "New FSI Buildable Area": f"{new_area:.2f} sq.ft",
-        "Total Area Gain": f"{area_gain:.2f} sq.ft",
-        "Premium FSI Portion": f"{premium_area:.2f} sq.ft",
-        "Premium FSI Charges": f"₹ {premium_fsi_charge:,.2f}",
-        "Total Construction Cost (New FSI)": f"₹ {total_construction_cost:,.2f}",
-
-        "--- Builder Deal Analysis ---": "",
-        "Builder Share Area": f"{builder_share_area:.2f} sq.ft",
-        "Owner Share Area": f"{owner_share_area:.2f} sq.ft",
-        "Resale Value (Builder Area @ Market Rate)": f"₹ {resale_value_builder:,.2f}",
-        "Construction Cost for Builder": f"₹ {construction_cost_builder:,.2f}",
+        "Total UDS": f"{uds:.2f} sq.ft",
+        "Total Built-up Area (2.8 FSI)": f"{total_built_up_area:.2f} sq.ft",
+        "Owner Entitlement Area (2.0 x UDS)": f"{owner_total_area:.2f} sq.ft",
+        "Builder Saleable Area (0.8 x UDS)": f"{builder_area:.2f} sq.ft",
+
+        "--- Builder Financials ---": "",
+        "Premium FSI Charges (0.4 × guideline × area)": f"₹ {premium_fsi_charge:,.2f}",
+        "Total Construction Cost (entire 2.8x)": f"₹ {total_construction_cost:,.2f}",
+        "Builder Revenue (@ market rate)": f"₹ {builder_sale_value:,.2f}",
         "Estimated Builder Profit": f"₹ {builder_profit:,.2f}",
 
-        "--- Owner Breakdown (based on UDS) ---": "",
+        "--- Owner Breakdown ---": "",
+        "Number of Owners": num_owners,
         "UDS per Owner": f"{uds_per_owner:.2f} sq.ft",
-        "New Area per Owner": f"{new_area_per_owner:.2f} sq.ft",
-        "Net Gain per Owner": f"{net_gain_per_owner:.2f} sq.ft"
+        "New Flat per Owner (2x UDS)": f"{owner_area_per_owner:.2f} sq.ft"
     }
 
     return result, fig
 
-# Gradio Interface Setup
+# Gradio Inputs and Outputs
 inputs = [
-    gr.Number(label="Current UDS (in sq.ft)", value=450),
+    gr.Number(label="Total UDS (in sq.ft)", value=450),
     gr.Number(label="Number of Owners", value=4),
-    gr.Number(label="Old FSI", value=1.5),
-    gr.Number(label="New FSI (max 2.8)", value=2.8),
     gr.Number(label="Guideline Value (₹/sq.ft)", value=5000),
-    gr.Number(label="Market Rate (₹/sq.ft for sale)", value=9500),
+    gr.Number(label="Market Rate (₹/sq.ft)", value=9500),
     gr.Number(label="Construction Cost (₹/sq.ft)", value=3500),
-    gr.Number(label="Current Total Area (in sq.ft)", value=1800),
-    gr.Slider(label="Builder Share (%) of Redeveloped Area", minimum=0, maximum=80, step=1, value=40)
 ]
 
 outputs = [
     gr.JSON(label="CMDA Redevelopment Report"),
-    gr.Plot(label="FSI Area Comparison Chart")
+    gr.Plot(label="Redevelopment Share Chart")
 ]
 
+# Interface setup
 app = gr.Interface(
-    fn=cmda_redevelopment_fsi_calculator,
+    fn=cmda_redevelopment_final_model,
     inputs=inputs,
     outputs=outputs,
-    title="CMDA Redevelopment Calculator with Builder Profit Estimator",
+    title="CMDA Redevelopment Calculator - Owner-Builder Model (Fixed FSI)",
     description=(
-        "Compare old and new FSI, calculate premium FSI charges, construction costs, and simulate builder profit "
-        "based on market resale rate. Assumes equal UDS share among owners."
+        "This calculator assumes owners are returned flats at 2x their UDS (normal FSI), and builder gets the premium FSI portion (0.8x UDS) "
+        "to sell. Builder pays full construction cost for entire 2.8x area and premium FSI charges."
     )
 )